staging: comedi: mite: do mite_steup() as part of mite_attach()

Currently all the drivers that use the mite driver have to call
mite_setup() after allocating and initializing the mite device
with mite_attach().

Move the mite_setup() call into mite_attach() to simplify the
drivers a bit and remove the need for the additional inline and
exported functions.

For aesthetics, move mite_setup2(), and rename it to mite_setup(),
so it's near mite_attach().

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>